Loud-speaker



Dec. 9, 1930. M. R. HUTCHISON 1,784,594

LOUD SPEAKER Filed Feb. 9. 1926 ATTORNEY Patented Dec. 9, 1930 UNITED STATES PATENT OFFICE MILLER REESE HUTCHIBON, OF LLEWELLYN PARK, WEST ORANGE, NEW JER$EY, AS-

SIGNOR, BY MESNE ASSIGNMENTS, TO ACOUSTIC PRODUCTS COMPANY, OF NEW YORK, N. Y., A CORPORATION DELAWARE LOUD-SPEAKER Application filed .i'ebruary ception, all as hereinafter will be more fully described and the claims.

Referring to the accompanying drawings forming a part of this specification in which particularly pointed out in like numerals designate like parts in all the views Figure 1 is a sectional view through a desigp of one of my improved resonating units.

igure 2 is an 'elevationaland diagrammatic view of one method of associating or connecting 'a plurality of these resonating unlts of progressive characterlstlcs, to a source or sources of energy or sound produc:

in impulses. so i igure 3 is a section through one of my horns or sounding devices adapted for resonance adjustability.

Figure 4 is a modification of one of my sound projections without a diaphragm in which I employ a musical are, for example.

In order that the precise nature of the invention may be better understood, it is pointed out that it is most desirable in a loud speaker, and especially so in the reproduction of vocal and instrumental music as received over the radio, to reproduce faithfully the many tones and overtones inherent in the full musical scale, and moreover to reproduce them with a 'full and comparable volume of sound to that of the original propagation.

9, 1926. Serial No. 87,078.

Not only may this be accomplished in a very superior manner with my instrument, but I am enabled to reproduce vocal and instrumental music with less volume and with greater volume respectively, to fully meet the requirements of the room or auditorium, where the reproduction is desired to be delivered.

As will be seen my instrument embodies a plurality of adjusted or adj ustably tuned resonating horns or sounding devices in association with a source of sound producing energy.

In my fully developed instrument I,furthermore associate a plurality of complete tuned or tunable resonative electromagnetic devices including their casings and contents,

be the said contents air or as, as well as their diaphragms and horns. plan, comprising a liberal plurality of my complete resonative unit systems, let us say twelve in number, the acoustic tuning of the system enables me to cover the entire musical sca e.

With further reference to Figure 1, 10 is the horn tube'of cylindrical bore adapted to be varied easily in length, with one end flared bell shaped at II and the other end terminating in a pipe-end joint adapted to fit over the extension neck piece 13 of the member 14 with its clear open throat 15, and making a smooth internal bore from the interior '15 of the said clear open throat to the interior 16 of the horn tube 10. Screw threads 17, 17, unite the member 14 securely with the casing 18 and clamping the diaphragm 19 securely by virtue of the shoulder 20 on the member 14. I have made many experiments with cork washers or rings, and find in some cases superior results attain, since the iron sheet from which the diaphragms are cut, does not always run uniform in thickness, due to faults y virtue of this in the rolling process of the metal or to oxidation.

An electro-magnet 21 is shown within the casing 18 supported at the back of said casing by the screw threaded portion with the screw driver slot 23, and secured by the lock nut 24. Binding posts 25. 25, anchor the ends of the coil winding of the said electromagnet. This electro-magnet may be of any suitable construction whereby it resonates electrically with the frequency of any applied current comparable to the frequency of the diaphragm and thus to any desired musical note.

'ith further reference to Figure 2. 36, and 37. are electrical conductors or leads to a suitable source of undulating or varying energy having speech, song, or instrumental music characteristics, and :28, and 29, are parallel electrical connections to the respective binding posts 25, 25. 25. 25, etc. of a plurality of resonative units as shown in Figure 1 of progressive or cl'ianging dimensions or characteristics. Inasmuch as progressive increase. or progressive decrease in diaphragm thickness constitutes one of my features of refinement in securing complete resonance of the unit to which it is associated. I'am illustrating four diaphragms removed from the instruments at 19, 19, 19, 19. Insomuch as it is impractical to show minute differences in diaphragm thickness in a drawing properly, since these thicknesses may vary by only a few thonsandths of an inch. I am covering the matter here by stating that the diaphragms 19. 19, 19, 19, from left to right in Figure 2, or from the shorter horns to the longer horns, decrease in thickness by a few thousandths of an inch. Again I may secure the same diaphragm adjustability as to resonance for different notes, by weighting the said diaphragms at or near their central portions. I am illustrating this weighting principle on the removed diaphragms 26, 26. 26, 26. showing the increasing weights or masses of material 2T, 2T, 2T, 27. It is pointed out that this weighting system conveniently makes the diaphragm adjustable.

It will now be appreciated from a careful inspection of one of my resonating units, as shown in cross section in Figure 1, that I secure maximum resonance for any tone by first adjusting and tuning the electro-magnetic system. then the diaphragm. then the length of the casing and its contents of air or gas, and then the horn tube length, or other suitable sounding device. It is extremely important that the casing containing the electro-magnetic device and the diaphragm be absolutely. air tight, that is to say that there is no escape of the confined air or gas from behind the diaphragm, since I have found that a slight pressure of air or gas upon the back of the diaphragm, gives it a slight convex surface next to the horn and makes it more responsive. Thus it may be seen that for perfect resonance all four of the important factors, the electro-magnet, the diaphragm, the casing with its contents of air or gas under slight pressure, and the horn, are adjusted for the perfect resonance of the unit and the association of a plurality of such adjusted and adjustable units produces an instrument of very superior characteristics over any heretofore devised.

Vith further reference to Figure 3, 10, is the horn tube, 11, is the bell flare, 12, is the pipe-joint end. 16 is the bore of a length of an outside sliding member, and 28 is an inside sliding member with its internal bore 29, and its beveled termination 30. This adjustability for resonance is admirable.

With further reference to Figure 4, 10 is the horn tube, 11 the flared bell shaped end, 16 the interior bore, 18 a modified casing 31, 31, insulating bushings, and 32, 32, carbon pencils or electrodes of any other suitable material. 33, 33, are electrical conductors leading to a source of undulating or interrupted electric energy or to the circuit of musical are. or to a high potential electrical generator and condenser or any other source of suitable electrical energy. A musical arc may here be established, or a succession of electric sparks of such frequencies as to produce musical notes.

Since all sounds are mechanical vibrations, and all physical structures and systems have their inherent vibrations of maximum efficiency, the tuning of my units with or without diaphragms, for perfect resonance, and

their association into a battery, gives a highly economic and scientific instrument when connected to a source of sound producing energy. And this economy applies also to the question of power or energy required to operate it, apart from the volume and beauty of its reproductions, since resonating unit-s absorb less energy than those heretofore employed which have not provided for the resonance of all the factors.

Whereas I have shown parallel connections in the diagram of leads in Figure 2, which is a preferred plan, there may be some series connections under certain circumstances, and some possible combinations of series parallel connections, and whereas I have shown and described an electro-magnet device for vibrating the diaphragm in my units, I do not wish to confine myself to this specific device, since I may secure vibrations of diaphragm through other electric-responsive means,the expansion and contraction of a wire carrying a varying electrical current. for example, with one end attached to the diaphragm at or near its central point. and the other end attached to the back of the resonating case, or as described I may dispense with diaphragms altogether and set up vibrations within my tuned sounding horns or other devices by independent means.

Again I may employ different shapes of horns, or sounding devices or sound projectors, and of different materials, and again I may not use any horns or sounding devices at all, but rely upon the reproductions to be propagated from the diaphragms themselves,

5 and when these diaphragms are sufiiciently large, reproductions of vocal and instrumental music for some purposes are satisfactorily given.

Having described my invention, I claim 1. Acoustic apparatus comprising a plurality of individual units, each unit comprising a sound chamber containing fluid, tuned to a diflerent note and an energy transfer device acoustically connected to each of said chambers. and means for connecting said devices directly to a common channel carrying a complex wave form made up of a plurality of said notes.

2. A loud speaker comprising a plurality of individual units, each unit comprising a sound chamber having a fluid column tuned to a different note and an actuating device acoustically connected to said chamber, and means for impressing directly and simultaneously on all said devices a complex wave made up of a plurality of said notes.

3. Acoustic apparatus comprising a plurality of individual units, each unit comprising a casing having a note responsive element, and an actuating device cooperating with said element, said casings being of different size and containing fluid mediums tuned to difi'erent notes, and means for connecting said devices directly together.

4. A loud speaker comprising a plurality of individual units, each unit having an actuating device, a diaphragm and a sound pipe, open at the delivery end, said sound pipes being of diflerent lengths, and said dia 40 phragms being of a different weight to tune said units to different notes, and means for impressing a complex wave made up of a. plurality of difl'erent notes directly on said units.

5. Acoustic apparatus comprising a plurality of individual units, each unit comprising a casing having a note responsive element, and an actuating device cooperating with said element, said casings being of different lengths and containing fluid mediums tuned to difl'erent notes, and means for connecting together said devices.

6. Acoustic apparatus comprising a plurality of individual units, one for each note of a scale, each unit com rising a sound chamber defining a ponderable medium tuned to av single note of the scale and an energy transfer device, and means for connecting said devices to a common channel carrying a complex wave form made up of a plurality of said notes.

Signed at city of New York, in the county of New York and State of New York, this eighth day of February, A. D. 1926.

MILLER REESE HUTCHISON. 

